he Pal AS TV LOTrR. YY of INS Gat Ss: 
at the fame time it performs the office of ‘a 
fheath or cafe, wherein m the nerve lies in 
perfect fafety, fo that it appears to be faintly 
vifible through it; it may, however, be 
difengaged from this covering, and then its 
{piral windings appear fo admirably conftruct- 
ed m, that any perfon who contemplates this 
prodigy of nature, muft be aftonifhed and 
ftruck with amazement. 
That mufcular, and at the fame time mem- 
branous, little part which covers the nerves, 
is fo tender in this place, that it may be very 
eafily feparated, and divided into parts, with 
the point of a needle, or with an ivory bod- 
kin ; after which the mufcle refembles as it 
were a grey delicate membrane, Tab. IV. fig. 
vi.o. The nerve itfelf {wells by degrees into 
a globular form /, at the end of which is 
placed an eyeg; of which I {hall prefently 
fpeak particularly. 
The little nerves » of the two lower horns, 
do not arife direCtly from the brain, but have 
fome parts intervening ; but as to the twifted 
nerves s, which are conveyed towards the 
fore part of the skin, to the root or bafis of 
the horns, they have there the fame texture 
with that of the nerves that belong to the 
upper horns, though they have no eyes in the 
ends of them. ‘The fame order, in every 
refpect, the fame wifdom and providence, are 
manifefted in the conftruction of thefe lower, 
as we have before mentioned in relation to 
the upper, pair of horns. 
The two {maller of thefe little nerves 
fpring immediately from the bafis of the brain, 
and are difpatched in the fame manner as to 
the larger horns¢. In fine, all the mufcular 
parts of the palate, mouth, and jaws, which 
I fhall hereafter defcribe particularly, are 
furnifhed with two fmall nerves v, which ad- 
minifter to their motion; thefe I have repre- 
tented im, Tab. VI. fie. i. at the letters’ pd) 
where may be feen the method in which 
they are bent, when the brain is moved for- 
ward. 
Fig. vit. a. The eye itfelf is very confpi- 
cuous, and in fome degree of the form of a 
round onion; but is a little flatt or fmooth on 
the verge, and {wells fomewhat into a point 
where the fight is exerted. But I could not 
_ obferve that the eye has more than one coat, 
which covers it on the infide, and which I 
call the uvea; if this uvea be in the leaft, 
ever fo lightly, touched, it makes the place it 
lies on very black, like ink: this I fhall thew 
more clearly hereafter, for I now only defcribe 
the eye, as it appeared to me through a mi- 
crofcope. I here likewife thew the grey 
mufcular membrane 445, which covers the 
eye; and I alfo exhibit the manner, wherein 
the circumference of the eye is connected 
with it : the optic nerve c is here reprefented 
likewife larger than natural, and its texture 
and form are fhewn; and after what manner | 
the eyes are placed thereon. Here is likewife 
fhewn how the inverted horn d is conneéted 
47, 
to all thefe parts, and the cavity ¢it pafles 
through ; as alfo after what manner, and in 
what place, it is protuberant f, on account of 
the mufcle which draws it back into the 
body of the creature; and which is there fixed 
in the end of it. 
I have obferved five diftind and vifible 
parts in the eye of the Snail, as clear as the. 
fun at noon ; firft, the external coat; which J 
call the uvea ; afterwards on the infide, the 
aqueous, the chryftalline, and the vitreous, 
humours, with the arachnoide tunic. But 
who can credit this? for it feems indeed im- 
probable that on a point not bigger than the 
nib of a writing pen, fuch exquifite art, and 
fo many miracles, fhould be difplayed. But 
what is there that equals the power of God, 
who is the contriver and creator of all thefe 
things? nor can there be any room for chance 
here, unlefs in the opinion of thofe, who 
deftroy and reject the fteps of natural know- 
ledge, left they fhould afcend in her paths, 
and be led to the wifeft of architects ; and, by 
contemplating even the moft minute of his 
works, be incited to proftrate themfelves with 
a facred reverence, and moft profound humi- 
lity before him, bidding adieu to their own’ 
opinions and former life, which, without 
the love of God, has been hitherto addi@ed 
only to the world. 
If the uvea be viewed with a microfcope, 
it has the appearance of a turnip roafted in the 
fire, until it is very black, and burft in fome 
places ; and has fome vifible fimall fibres, which 
connect it with the adjacent parts. But when 
this eye and its coat are put, with a very fine 
pencil, into the fourth part of a drop of water, 
for more water would overflow it, and, after 
ftirring them a little, they are cautioufly and 
flowly touched; the water at length becomes 
black likewife, and fhews the remains of the 
particles {wimming in it: the fame thing will 
happen alfo if an experiment be made on the 
uvea of the human eye. But when all the 
moifture is wiped off clean, and a little wound 
is made in the eye with two fine and very tharp 
needles, Tab. IV. fig. vir. a, the aqueous 4 hu- 
mour will be obferved to burft out from thence. 
If this eye be afterwards prefs’d more roughly, 
you will fee a more clammy humour iffuing 
from thence ¢; which is properly the vitreous 
humour. And laftly, after that, the chryftalline 
humour, which is of a harder confiftence, and 
of a plane round figure d; it is limpid, tran{pa- 
rent and fhining ; but it does not ran out, until 
you break the arachnoide coat, which covers 
it, and which is the fifth part of this eye. From 
thefe obfervations we learn clearly, how “ the 
** invifible things of God, from the creation of 
** the world, are clearly feen, being underftood 
‘* from the things that are made, even his eter- 
*‘ nal power and godhead, fo that they are 
** without excufe, becaufe that when they 
** knew God, they glorified him not as God.” 
Seto. 020, 21. 
The 
